1 files changed, 349 insertions, 0 deletions
diff --git a/modules/git/repo_branch.go b/modules/git/repo_branch.go
new file mode 100644
index 0000000..7339c7d
--- /dev/null
+++ b/modules/git/repo_branch.go
@@ -0,0 +1,349 @@
+// Copyright 2015 The Gogs Authors. All rights reserved.
+// Copyright 2018 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package git
+
+import (
+	"bufio"
+	"bytes"
+	"context"
+	"errors"
+	"fmt"
+	"io"
+	"strings"
+
+	"code.gitea.io/gitea/modules/log"
+)
+
+// BranchPrefix base dir of the branch information file store on git
+const BranchPrefix = "refs/heads/"
+
+// IsReferenceExist returns true if given reference exists in the repository.
+func IsReferenceExist(ctx context.Context, repoPath, name string) bool {
+	_, _, err := NewCommand(ctx, "show-ref", "--verify").AddDashesAndList(name).RunStdString(&RunOpts{Dir: repoPath})
+	return err == nil
+}
+
+// IsBranchExist returns true if given branch exists in the repository.
+func IsBranchExist(ctx context.Context, repoPath, name string) bool {
+	return IsReferenceExist(ctx, repoPath, BranchPrefix+name)
+}
+
+// Branch represents a Git branch.
+type Branch struct {
+	Name string
+	Path string
+
+	gitRepo *Repository
+}
+
+// GetHEADBranch returns corresponding branch of HEAD.
+func (repo *Repository) GetHEADBranch() (*Branch, error) {
+	if repo == nil {
+		return nil, fmt.Errorf("nil repo")
+	}
+	stdout, _, err := NewCommand(repo.Ctx, "symbolic-ref", "HEAD").RunStdString(&RunOpts{Dir: repo.Path})
+	if err != nil {
+		return nil, err
+	}
+	stdout = strings.TrimSpace(stdout)
+
+	if !strings.HasPrefix(stdout, BranchPrefix) {
+		return nil, fmt.Errorf("invalid HEAD branch: %v", stdout)
+	}
+
+	return &Branch{
+		Name:    stdout[len(BranchPrefix):],
+		Path:    stdout,
+		gitRepo: repo,
+	}, nil
+}
+
+func GetDefaultBranch(ctx context.Context, repoPath string) (string, error) {
+	stdout, _, err := NewCommand(ctx, "symbolic-ref", "HEAD").RunStdString(&RunOpts{Dir: repoPath})
+	if err != nil {
+		return "", err
+	}
+	stdout = strings.TrimSpace(stdout)
+	if !strings.HasPrefix(stdout, BranchPrefix) {
+		return "", errors.New("the HEAD is not a branch: " + stdout)
+	}
+	return strings.TrimPrefix(stdout, BranchPrefix), nil
+}
+
+// GetBranch returns a branch by it's name
+func (repo *Repository) GetBranch(branch string) (*Branch, error) {
+	if !repo.IsBranchExist(branch) {
+		return nil, ErrBranchNotExist{branch}
+	}
+	return &Branch{
+		Path:    repo.Path,
+		Name:    branch,
+		gitRepo: repo,
+	}, nil
+}
+
+// GetBranches returns a slice of *git.Branch
+func (repo *Repository) GetBranches(skip, limit int) ([]*Branch, int, error) {
+	brs, countAll, err := repo.GetBranchNames(skip, limit)
+	if err != nil {
+		return nil, 0, err
+	}
+
+	branches := make([]*Branch, len(brs))
+	for i := range brs {
+		branches[i] = &Branch{
+			Path:    repo.Path,
+			Name:    brs[i],
+			gitRepo: repo,
+		}
+	}
+
+	return branches, countAll, nil
+}
+
+// DeleteBranchOptions Option(s) for delete branch
+type DeleteBranchOptions struct {
+	Force bool
+}
+
+// DeleteBranch delete a branch by name on repository.
+func (repo *Repository) DeleteBranch(name string, opts DeleteBranchOptions) error {
+	cmd := NewCommand(repo.Ctx, "branch")
+
+	if opts.Force {
+		cmd.AddArguments("-D")
+	} else {
+		cmd.AddArguments("-d")
+	}
+
+	cmd.AddDashesAndList(name)
+	_, _, err := cmd.RunStdString(&RunOpts{Dir: repo.Path})
+
+	return err
+}
+
+// CreateBranch create a new branch
+func (repo *Repository) CreateBranch(branch, oldbranchOrCommit string) error {
+	cmd := NewCommand(repo.Ctx, "branch")
+	cmd.AddDashesAndList(branch, oldbranchOrCommit)
+
+	_, _, err := cmd.RunStdString(&RunOpts{Dir: repo.Path})
+
+	return err
+}
+
+// AddRemote adds a new remote to repository.
+func (repo *Repository) AddRemote(name, url string, fetch bool) error {
+	cmd := NewCommand(repo.Ctx, "remote", "add")
+	if fetch {
+		cmd.AddArguments("-f")
+	}
+	cmd.AddDynamicArguments(name, url)
+
+	_, _, err := cmd.RunStdString(&RunOpts{Dir: repo.Path})
+	return err
+}
+
+// RemoveRemote removes a remote from repository.
+func (repo *Repository) RemoveRemote(name string) error {
+	_, _, err := NewCommand(repo.Ctx, "remote", "rm").AddDynamicArguments(name).RunStdString(&RunOpts{Dir: repo.Path})
+	return err
+}
+
+// GetCommit returns the head commit of a branch
+func (branch *Branch) GetCommit() (*Commit, error) {
+	return branch.gitRepo.GetBranchCommit(branch.Name)
+}
+
+// RenameBranch rename a branch
+func (repo *Repository) RenameBranch(from, to string) error {
+	_, _, err := NewCommand(repo.Ctx, "branch", "-m").AddDynamicArguments(from, to).RunStdString(&RunOpts{Dir: repo.Path})
+	return err
+}
+
+// IsObjectExist returns true if given reference exists in the repository.
+func (repo *Repository) IsObjectExist(name string) bool {
+	if name == "" {
+		return false
+	}
+
+	wr, rd, cancel, err := repo.CatFileBatchCheck(repo.Ctx)
+	if err != nil {
+		log.Debug("Error writing to CatFileBatchCheck %v", err)
+		return false
+	}
+	defer cancel()
+	_, err = wr.Write([]byte(name + "\n"))
+	if err != nil {
+		log.Debug("Error writing to CatFileBatchCheck %v", err)
+		return false
+	}
+	sha, _, _, err := ReadBatchLine(rd)
+	return err == nil && bytes.HasPrefix(sha, []byte(strings.TrimSpace(name)))
+}
+
+// IsReferenceExist returns true if given reference exists in the repository.
+func (repo *Repository) IsReferenceExist(name string) bool {
+	if name == "" {
+		return false
+	}
+
+	wr, rd, cancel, err := repo.CatFileBatchCheck(repo.Ctx)
+	if err != nil {
+		log.Debug("Error writing to CatFileBatchCheck %v", err)
+		return false
+	}
+	defer cancel()
+	_, err = wr.Write([]byte(name + "\n"))
+	if err != nil {
+		log.Debug("Error writing to CatFileBatchCheck %v", err)
+		return false
+	}
+	_, _, _, err = ReadBatchLine(rd)
+	return err == nil
+}
+
+// IsBranchExist returns true if given branch exists in current repository.
+func (repo *Repository) IsBranchExist(name string) bool {
+	if repo == nil || name == "" {
+		return false
+	}
+
+	return repo.IsReferenceExist(BranchPrefix + name)
+}
+
+// GetBranchNames returns branches from the repository, skipping "skip" initial branches and
+// returning at most "limit" branches, or all branches if "limit" is 0.
+func (repo *Repository) GetBranchNames(skip, limit int) ([]string, int, error) {
+	return callShowRef(repo.Ctx, repo.Path, BranchPrefix, TrustedCmdArgs{BranchPrefix, "--sort=-committerdate"}, skip, limit)
+}
+
+// WalkReferences walks all the references from the repository
+// refType should be empty, ObjectTag or ObjectBranch. All other values are equivalent to empty.
+func (repo *Repository) WalkReferences(refType ObjectType, skip, limit int, walkfn func(sha1, refname string) error) (int, error) {
+	var args TrustedCmdArgs
+	switch refType {
+	case ObjectTag:
+		args = TrustedCmdArgs{TagPrefix, "--sort=-taggerdate"}
+	case ObjectBranch:
+		args = TrustedCmdArgs{BranchPrefix, "--sort=-committerdate"}
+	}
+
+	return WalkShowRef(repo.Ctx, repo.Path, args, skip, limit, walkfn)
+}
+
+// callShowRef return refs, if limit = 0 it will not limit
+func callShowRef(ctx context.Context, repoPath, trimPrefix string, extraArgs TrustedCmdArgs, skip, limit int) (branchNames []string, countAll int, err error) {
+	countAll, err = WalkShowRef(ctx, repoPath, extraArgs, skip, limit, func(_, branchName string) error {
+		branchName = strings.TrimPrefix(branchName, trimPrefix)
+		branchNames = append(branchNames, branchName)
+
+		return nil
+	})
+	return branchNames, countAll, err
+}
+
+func WalkShowRef(ctx context.Context, repoPath string, extraArgs TrustedCmdArgs, skip, limit int, walkfn func(sha1, refname string) error) (countAll int, err error) {
+	stdoutReader, stdoutWriter := io.Pipe()
+	defer func() {
+		_ = stdoutReader.Close()
+		_ = stdoutWriter.Close()
+	}()
+
+	go func() {
+		stderrBuilder := &strings.Builder{}
+		args := TrustedCmdArgs{"for-each-ref", "--format=%(objectname) %(refname)"}
+		args = append(args, extraArgs...)
+		err := NewCommand(ctx, args...).Run(&RunOpts{
+			Dir:    repoPath,
+			Stdout: stdoutWriter,
+			Stderr: stderrBuilder,
+		})
+		if err != nil {
+			if stderrBuilder.Len() == 0 {
+				_ = stdoutWriter.Close()
+				return
+			}
+			_ = stdoutWriter.CloseWithError(ConcatenateError(err, stderrBuilder.String()))
+		} else {
+			_ = stdoutWriter.Close()
+		}
+	}()
+
+	i := 0
+	bufReader := bufio.NewReader(stdoutReader)
+	for i < skip {
+		_, isPrefix, err := bufReader.ReadLine()
+		if err == io.EOF {
+			return i, nil
+		}
+		if err != nil {
+			return 0, err
+		}
+		if !isPrefix {
+			i++
+		}
+	}
+	for limit == 0 || i < skip+limit {
+		// The output of show-ref is simply a list:
+		// <sha> SP <ref> LF
+		sha, err := bufReader.ReadString(' ')
+		if err == io.EOF {
+			return i, nil
+		}
+		if err != nil {
+			return 0, err
+		}
+
+		branchName, err := bufReader.ReadString('\n')
+		if err == io.EOF {
+			// This shouldn't happen... but we'll tolerate it for the sake of peace
+			return i, nil
+		}
+		if err != nil {
+			return i, err
+		}
+
+		if len(branchName) > 0 {
+			branchName = branchName[:len(branchName)-1]
+		}
+
+		if len(sha) > 0 {
+			sha = sha[:len(sha)-1]
+		}
+
+		err = walkfn(sha, branchName)
+		if err != nil {
+			return i, err
+		}
+		i++
+	}
+	// count all refs
+	for limit != 0 {
+		_, isPrefix, err := bufReader.ReadLine()
+		if err == io.EOF {
+			return i, nil
+		}
+		if err != nil {
+			return 0, err
+		}
+		if !isPrefix {
+			i++
+		}
+	}
+	return i, nil
+}
+
+// GetRefsBySha returns all references filtered with prefix that belong to a sha commit hash
+func (repo *Repository) GetRefsBySha(sha, prefix string) ([]string, error) {
+	var revList []string
+	_, err := WalkShowRef(repo.Ctx, repo.Path, nil, 0, 0, func(walkSha, refname string) error {
+		if walkSha == sha && strings.HasPrefix(refname, prefix) {
+			revList = append(revList, refname)
+		}
+		return nil
+	})
+	return revList, err
+}